Photographic processing apparatus



June 11, 1963 w. c. BURNER ETAI. 3,093,052

PHOTOGRAPHIC PROCESSING APPARATUS Filed Dec. 3. 1959 2 Sheets-Sheet 1cHm STOPHER LUCAS ATTO June 11, 1963 W. C. BURNER ETAL PHOTOGRAPHICPROCESSING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 3. 1959 FIG?)INVENTORS,

WILLARD C. BURNER SEYMOUR 1.. HER SH CHRISTOPHER LUCAS ATTO NE UnitedStates Patent 3,093,052 PHOTOGRAPHIC PRUCESSING APPARATUS Willard C.Burner, Lincroft, Seymour L. Hersh, Freehoid,

and Christopher Lucas, Long Branch, NJL, assignors to the United Statesof America as represented by the Secretary of the Army Filed Dec. 3,1959, Ser. No. 857,238 1 Claim. (Cl. 95-94) (Granted under Title 35, US.Code (1952), sec. 266) The invention described herein may bemanufactured and used by or for the Government for governmentalpurposes, without the payment of any royalty thereon.

This invention relates to method and apparatus for processing photosensitive materials and provides particularly for continuous rapidprocessing of strip type materials.

The techniques involved in the invention are adapted to the use ofelevated temperature development and fixing in which case it is possibleto completely process as much as 100 feet of 35 millimeter film perminute. However normal temperature processing may be executed atrelatively fast speeds by the use of the apparatus of the invention.

As will appear hereinafter the invention is adaptable to variousprocessing systems such as the so-called monobath system and thestabilization technique.

The apparatus of the invention makes possible successful processing athigh speed and is briefly described as follows. A plurality ofprocessing wheels are rotatively mounted upon one face of a verticalpanel of chemically resistant material which physically separates thechemical manipulating elements from the driving and control mechanism.The wheels are arranged to be sequentially contacted by the strip to beprocessed along a portion of their periphery.

The whole apparatus may be operated Within the confines of a dark roomor may be enclosed in a light tight casing of its own not shown. In thelatter case suitable control adjustments will be made accessible outsidethe casing.

Each wheel is partially submerged in a tank of processing solution andis rotated by suitable driving means. Guiding means is provided tocontrol the lateral position of the strip upon the roll. The faces ofthe processing wheels are treated to enable them to pick up solution andapply it to the emulsion side of the strip only. The width of the faceof the applicator wheels is less than the total width of the strip. Inthis manner development of the exposed main area of the film isprocessed while the narrow margins are not processed. This techniqueinsures that no solution will accumulate on the back of the film tocause stains, streaks or other imperfections and also eliminates an allover Washing step.

The peripheral faces of the applicator Wheels maybe treated or coveredwith material which serves to absorb solution for transfer to the filmand at the same time protect it from scratches and imperfections whilebeing processed. A valuable feature of the invention lies in theformation of a series of narrow deep slots extending transversely acrossthe face of the wheel. These slots function to reduce the drag on thestrip which may become excessive. The drag is induced by the film ofsolution between the contacting surfaces of the wheels and strip.Additional features of the invention will be described hereinafter inconnection with a detailed description thereof.

A primary object of the invention is to provide an extremely rapidsystem for processing photographic images.

A further object of invention is to provide a photo processing apparatuscapable of rapidly processing photo "ice sensitive materials and whereinmost of the variables effecting the quality and characteristics of thefinished image are under control.

A still further object of the invention is to provide safe and effectivemeans for high speed processing of photo materials at high leveltemperatures.

A further object of the invention is to provide very compact means forrapidly processing long lengths of photo sensitive materials.

A still further object of the invention is to provide a processingapparatus which is rapid in action and which lends itself to thepractice of a variety of techniques.

A further object of the invention is to provide a substantial economy inconsumption of solution.

Other objects and features of the invention will more fully appear fromthe following description and will be particularly pointed out in theclaim.

To provide a better understanding of the invention specific embodimentsthereof will be described in connection with the accompanying drawingswherein:

FIG. 1 is a side elevation of an apparatus embodying the invention.

FIG. 2 is a partial diagrammatic plan view of the apparatus showing thedriving means.

FIG 3 is an enlarged vertical cross section on line 33 FIG. 1 showingthe detail structure of the applica tor Wheels.

FIG. 4 is a detail showing the structure of squeegee means 'for theapplicator wheels.

FIG. 5 is a detail showing of the structure mounting the roll coveringto an applicator wheel.

The arrangement of the elements of the device as shown in the drawingshas been found to be satisfactory. It should be understood however thatother suitable arrange ments may be made without departing from thespirit and scope of the invention. Desirably the rotating processingelements are mounted upon a vertical panel 10 which in turn is securedto a suitable base 11. The panel serves not only as a support but alsoas a shield to separate the driving elements from the processingelements thus to protect the driving elements from corrosion.

A plurality of applicator wheels are rotatively supported on the panel10 the number of such Wheels being determined by the processing stepsrequired for a given processing system. As shown in FIG. 1, there arethree applicator wheels. The first wheel from left to right is thedeveloper applying wheel 12, the second wheel 13 is for fixing and thethird wheel 14 is for rinsing or other finishing operation. Otherfunctions may be assigned to the wheels.

Each wheel is supported upon and driven by suitable shafts 15, which arejournaled in bearings 16 fastened to the panel 10. The shafts extendoutward from both sides of the panel and are connected to the drivemechanism at one end and receive the applicator wheels at their otherend. Suitable coupling arrangement is made between the shafts and thewheels. In the embodiment shown the shafts are squared in cross sectionto be received in snugly fitting square apertures in the wheels. Meansare also provided to detachably lock the Wheels upon the shafts such asthe wheel securing device 17 having a locking arm movable from its wheeldetaching position in alignment with the shaft, to its locking positiontransverse to the shaft where it engages the hub of the Wheel to retainit in operating position.

Processing tanks 18, 19 and 29, of stainless steel or any non-corrosivematerial are provided into which the applicator wheels 12, 13 and 14-respectively dip to pick up solution to be fed to the strip. The tanksmay receive solution thru a piping system from a larger supply containeror as shown each tank may be removable and adapted to be filled bymanual means. They may be hung upon the panel or rest upon the base 11.Each tank is provided with an electric heater 21 having temperaturecontrolling means.

The wheels as shown are about six inches in diameter and have aperipheral face of a width to receive a conventional edge perforated 35mm. film strip. Other wheels can be supplied and placed on the shafts toaccommodate other sizes of film or printing paper strips. The diameterof the wheels is determined by the size of the equipment, capacity ofsolution tanks, the desired maximum required degree of contact betweenthe film and wheel faces as it progresses thru its processing stages andother factors which are matters of design. The driving means willsubsequently be described in connection with the description ofoperation of the device.

Processing solutions are applied only to the emulsion side and only tothe actual picture area. No solution is applied to the margins of thestrip. To accomplish this specific result the exposed film or paperstrip 23 is wider than the faces of the wheels 12, 13, and 14. The stripis fed from a supply reel 24 to the first applicator wheel 12 passingover a guide roll 25 and thence along a portion of the upper peripheryof the wheel 12 and is led off this Wheel by a second guide roll 26 fromwhere it passes to wheel 13. It then passes to guide rolls 2.7 and 23and thence to the wheel 14 after which it passes around guide roll 29.The guide rolls are undercut to avoid contact with the center portion ofthe strip. From the roll 29 the strip is fed to a driving sprocket 3tengaging the edge perforations of the strip. From the sprocket the Stripis led to a suitable drying device 31. The strip when dry is then readyfor use.

Means are provided for varying the contact area between the wheels andthe film strip. A suitable means for accomplishing this adjustment is torotatively support the guide rolls upon removable stud shafts 32 havingtheir threaded inner ends projecting thru the panel 10 and provided witha nut or thumbscrew to effect detachable mounting upon the panel.

A row of apertures 33 are provided in the panel equidistant from eachroll axis and within which the roll support shaft 32 may be received toprovide the required degree of wrap of the strip around the wheel face.The guide rolls are provided with side flanges between which the stripis caused to track properly while passing over the applicator wheels.

A further operating facility is provided for prewetting the emulsionprior to its development. Any suitable means may be provided for thispurpose such as the roll 34 of the same Width as the applicator wheel,which is so positioned that it will engage the emulsion side of thestrip before it reaches the Wheel 12. The roll desirably is covered withabsorbent material and dips into a water tank 35. A hold down roll 34Xis removably mounted on the panel 10 and engages the back of the strip23 to press it into contact with the wheel 34. In this manner water isconveyed to the emulsion on the strip. This prewetting step is used incertain developing techniques the details of which will be set forthhereinafter.

The roll 34 is operated by a variable speed reversible drive mechanism22. It is important to apply the water evenly and rapidly to the strip.This is accomplished by driving the roll either at a peripheral speedfaster or slower than the linear speed of the strip. Optimum results areobtainable by accurate adjustment of the roll speed. If the peripheralspeed of the roll is equal to and in the same direction as that of thestrip, the finished image may show an uneven pattern imparted thereto bythe pattern of the surface of the roll.

The ability to reverse the rotation of the roll 34 and also theapplicator wheels provides flexibility in adjusting the total drag onthe strip during its progress thru the apparatus. By selecting theproper rotation for these elements the drag upon the strip due to onemay at least partially cancel that due to another. Thus the total dragmay be kept to minimum.

it is also desirable to provide squeegee rolls 36 to re move surplussolution from the peripheral faces of the applicator wheels as theycarry solution from the tank toward the strip. The squeegee must bepositioned to engage the wheel at a point to prevent the surplussolution rom reaching the film such as between the surface of thesolution and the first line of contact of strip and wheel. The contactpressure of the squeegee roll is adjustable to insure the correctquantity of solution reaching the strip emulsion. This adjustment may beprovided by mounting each squeegee roll on a shaft 37 which is securedto a swinging arm 38 having a shaft 39 pivoted within the panel 19 topermit the roll 36 to move toward and from the applicator wheels.

The pivot shaft 39 extends thru the panel and has an arm 46 securedthereto, to which is fastened one end of a spring 41, the other end ofwhich is fastened to a stud 4-2. The stud is adjustably secured in aslot 43 in the panel thereby to provide adjustment of the spring tensionand thus to vary the pressure of roll 36 on its applicator wheel. Othermeans may be devised to mount the squeegee rolls 36.

Two squeegee rolls 36 are provided for applicator wheels 13 and 14 andone for wheel 12. In addition latching pins 44 are provided. These pinsare removably mounted on the panel 10 and project into the path of thearms 40 on the squeegee control devices. When in inactive position theylock the rolls 36 out of action as shown in dotted lines FIG. 4. Thiscontrol of the rolls 36 is provided to permit selective operationthereof thus to prepare the apparatus for various modes of operation. Insome instances the direction of operation of certain of the applicatorwheels are reversed as pointed out above therefore the proper roll 36must be rendered operative and the other rolls inoperative.

Any suitable means may be used to drive the applicator rolls. As shownin FIG. 2, the wheels are driven by re versible variable speed electricmotors 45 and 46 secured to the base 11. Motor 45 drives applicatorwheel 12 thru a speed reducing mechanism 47 connected to the drive shaftof the wheel. Motor 46 drives wheels 13 and 14 respectively thru speedreducing mechanisms 48 and 49 coupled to the drive shafts of the Wheels.

Desirably the roll 12 is driven in such direction that its peripherymoves in the opposite direction to that of the movement of the strip andmoreover since the mo tor 45 is a variable speed motor the degree ofcounter motion is adjustable. Desirably the strip is drawn thru theapparatus by means of a sprocket Wheel 30 engaging the edge perforationsof the strip. If no perforations are present the sprocket may bereplaced by a friction type drive wheel engaging the edges of the strip.The sprocket 30 is driven by the motor 46 in any suitable manner such asby the chain and sprocket drive 51. Desirably a hold down roll may beprovided for :ZnJaintaining engagement between the strip 23 and sprocketThe wheel 13 is driven in the same direction and at a peripheral speedfaster than that of the travel of the strip. The roll 14 is driven in adirection counter to that of roll 13. To provide for such change indirection a reversing mechanism 52 is inserted in its drive shaft. Othersuitable driving means for the strip and applicator wheels may be used.

An important feature of the invention resides in provision for feedingcontrolled amounts of solution to the strip being processed. Accurateand uniform feeding of processing solutions is highly desirable. This isespecially true in the present invention where high speed is a mainobjective. A positive flow of solution in adequate amount must besupplied but not in excess thereof because waste of solution anduncontrollable distribution thereof would render the apparatusineffective and inetficient.

The above described squeegee rolls 36 constitute a portion of thecontrol means for applying solution to the strip 23. An important andnovel feature of the invention resides in the further improvement of thesolution applying means. This further improvement is directed to theprovision of the most effective peripheral surface structure for thewheels 12, 13, and 14. Consideration of many factors entered into thedevelopment of the most effective means for carrying solutions fromtheir tanks to the surface of the strip along the periphery of theapplicator wheels. It was found that an effective carrier means was tocover the wheel surfaces with a fabric having the ability to absorbsubstantial quantities of solution and to feed the solution to theemulsion on the strip, thruout its traverse of the contact areas of thewheel, at a uniform rate. The fabric must also be soft to avoid abrasionof the softened emulsion which, at high temperatures in particular, issubject to damage. Such a covering is shown in FIG. 3 and consists of astrip of fabric 53 covering the wheel face from edge to edge. The fabricis composed of a relatively thick base portion 54 and an interwovenshort pile structure 55 presenting the desired soft contact betweenstrip and wheel. This fabric absorbs a substantial volume of solutionfrom a tank and applies it evenly to the strip by contact of its pilestructure therewith, the operation being similar to painting with a softbristle brush. The margins 56 of the strip beyond the edges of the rolldo not receive processing solution.

When applicator rolls are covered as shown in FIG. 3 solution of normalconcentration may be used and prewetting is not necessary but may stillbe used. The water feeding roll 34 may be rendered inactive by removingthe contact roll 34X and the film strip led from its supply roll 24directly to the guide roll 25 and thence over the upper portion of theroll 12 after which the strip follows the path of travel set forthabove. The roll 12 performs the developing operation by carrying heateddeveloper from the tank 18, upward to the strip 23. Surplus solution iscontrolled by the squeegee 36- whose contact pressure may be adjusted asdescribed above.

The tank 19 contains a fixing solution heated by its heater 21 andapplied to the strip by the roll 13 as in the developing step. In thespecific procedure herein described above the roll 13 is driven toprovide faster peripheral speed than the strip. Surplus solution iscontrolled by its left hand squeegee 35 while its other squeegee islatched out of operation. The tank 20 contains rinse water which acts toremove unwanted chemicals from the emulsion of the strip and surplusmoisture is controlled by the right hand squeegee. When dried the stripis clear and free of defects and stains and moreover the limited amountof moisture contained in the emulsion is rapidly removed with a minimumof heating currents consumed by the drying chamber 31.

The slots 57 in the rolls 12, 13, and 14 extend transversely acrosstheir faces and are cut deeply radially inward. These slots function torelieve drag on the strip and to aid in feeding solution to the rollcovering 53 when it is immersed in the solution. Suitable means areprovided to clamp the roll covering 53 upon the roll. One such means isto provide a slot in the face of the roll within which the ends of thematerial are held by a wedging block 58.

Guide blocks 59 are fastened to the panel in position to engage theinner edge of the strip 24 and guide rods 60 are anchored in the paneland bent downward to embrace the outer edge of the strip. The strip isthus accurately guided and centered on the rolls. The guide means maypresent any portion of the inner area of the strip to the wheels.

The various elements of the apparatus may be operated in various waysother than in the above specified manner to enable different types ofsensitive materials to be processed for example development, shortstopand fixing may be sequentially executed by the wheels 12, 13, and 14.Additional applicator wheels may also be added when necessary.

The applicator rolls may be made of any suitably noncorrosive materialsuch as hard rubber or various synthetic materials such as polyethelene.As above pointed out excellent results are obtained by covering thewheel faces with selected fabrics. However it may be found desirable to.use smooth faced rolls without covering. When smooth rolls are used onlya small amount of solution adheres to the wheels which may not :besufiicient to properly process the emulsion particularly at the highspeeds for which the invention is adapted.

To overcome this deficiency special formulations are used for theprocessing solutions wherein the chemicals are incorporated at highconcentrations. The higher concentration of the solution applies a muchhigher processing potentiality to the emulsion. However, the highconcentration solution does not of itself readily permeate the emulsion.To overcome this deficiency the prewetting roll 34 is activated bymounting the roll 34X in position and the strip passed between it andthe roll 34. The emulsion thus moistened will more readily accept anddiffuse the processing chemicals to provide fast and uniform action ofthe solution.

Under certain conditions it is desirable to use smooth faced uncoveredapplicator rolls because there is no covering material to replace whenit "becomes worn. Also there is less chance of picking up harmful smallabrasive particles and the drag upon the strip is lessened.

A highly effective use of the invention is in the practice of the socalled stabilization process as set forth in US. Patent No. 2,696,439wherein photo sensitive material is first developed in any suitablemanner and then instead of fixing the material the unexposed and nudeveloped silver halide remaining after development is rendered neutraland transparent.

The present invention provides a practical manner in which this processmay be greatly speeded up. By conducting the processes at elevatedtemperatures the development time is shortened and in addition thestabilization time may be greatly reduced. In normal practice thestabilizing or clearing step consumes more time than the development. Itfollows that time reduction of this step is most important in reducingthe total processing time.

Stabilization is accomplished by bathing the material in a solution ofthiourea. Higher concentrations of this compound tends to speed up thestabilization step. However, there normally is a limit to the degree ofconcentration because when too much thiourea is used crystallization ofthe excess thereof takes place upon the emulsion surface which degradesthe quality of the image.

In practicing the stabilization process upon the apparatus of theinvention a high temperature development step is followed by a hightemperature stabilization step wherein an increased concentration ofthiourea is used which greatly reduces the time for clearing of theimage. Under these conditions an abnormal amount of thiourea is presenton the emulsion surface and if left to dry would not be tolerable.Therefore the last processing wheel 14 having a fabric covering thereonis used to wash the emulsion surface with water which removes thesurplus thiourea. This washing step can not be done by any prior knownmeans but is successfully accomplished by the apparatus of thisinvention.

In the present invention each step in the process is executed veryrapidly. As a consequence the emulsion does not swell and soften to theextent it would at conventional processing speeds. This is especiallytrue in the case of the high thiourea concentration as above statedwhich may be 11% at 68 F. which is the saturation level. Temperaturesused maybe as high as or higher in which case thiourea would be added toproduce substantial saturation. It is possible therefore to safely washoff the excess of thiourea in the last step of the process. Thus thewhole operation is greatly speeded up. It should be noted that in theevent that a greater or less number of processing wheels than thoseshown and described are provided, the step of removing surplus thioureaor any chemical appearing in excess upon the strip may be removed by awashing wheel arranged to follow the final processing step.

What is claimed is:

Apparatus for continuous processing of photosensitive strip materialscomprising a plurality of rotatively mounted solution applying wheelshaving a solution absorbing soft fabric peripheral face, a solutioncontaining tank for each wheel into which a portion of the wheel issubmerged, a supply roll containing the strip to 'be processed, means toguide said strip into successive peripheral contact with a portion ofthe unsubmerged periphery of said wheels, squeegee means acting on theperiphery of said solution applying wheels to prevent the passage ofexcessive solution from said tanks to the film strip, a driving systemto drive said wheels consisting of at least one film strip feeding rollhaving means to advance the film through the apparatus at a given speedindependently of the peripheral speed or direction of rotation ofcertain of said wheels, variable speed driving means for said wheelshaving means for independently reversing the rotation of some of saidwheels, said driving system driving said wheels at different speeds andin diiferent relative directions of rotation to reduce excessive drag onthe film strip and to provide for applying variable amounts of solutionper unit area to said strip at selected solution applying wheels andwherein at least some of said solution applying Wheels are provided witha plurality of narrow slots extending from the periphery of the wheelradially inward in a plane parallel to the wheel axis acting to relievethe tendency of the strip to adhere to the wheel.

References Cited in the file of this patent UNITED STATES PATENTS

